J. Am. Chem. SOC.1986, 108, 8097-8098 Alfred P. Sloan Foundation for the award of a Fellowship. Supplementary Material Available: Tables of atomic coordinates, temperature factors, crystal data and data collection parameters, and bond distances and angles (1 3 pages); structure factor tables (12 pages). Ordering information is given on any current masthead page.
Kinetics of Intermolecular Oxidative Addition of Primary, Secondary, and Tertiary CH Bonds to (OC)3MnRichard N. McDonald* and Michael T. Jones Department of Chemistry, Kansas State University Manhattan, Kansas 66506 Received July 21, 1986
Intermolecular oxidative addition of alkane C H bonds to coordinatively unsaturated transition-metal complexes continues as an intriguing area of research in organometallic chemistry' since the first reports by Janowicz and Bergman2 and Hoyano and Graham3 in 1982. While oxidative addition of primary and secondary alkane CH bonds to several metal complexes are well established, we are not aware of success in oxidatively adding alkane tertiary CH bonds to metal complexes! We wish to report kinetic evidence that (OC)3Mn- oxidatively adds isobutane by competitive insertion of the metal into the primary and tertiary C H bonds and that the relative rates for the oxidative addition of CH bonds to (OC)3Mn- are primary (1 ") < secondary (2') < tertiary (3'). Our studies are carried out in a previously described flowing afterglow apparatus., A mixture of (OC),Mn- ( m l z 195), (OC)4Mn- ( m l z 167), and (OC)3Mn- ( m l z 139) is produced by dissociative attachment of energetic electrons with Mn2(CO)lo in a fast flow of helium buffer gas (PHc= 0.7 torr, 0 = 58 m/s) at 298 K.6 Neither (OC),Mn- or (OC)4Mn- react with the cm3 molecule-' s-I). alkanes under these conditions ( k < Addition of C2H6to the flow containing the 14-electron (OC),Mn- gave attenuation of the signal for m / z 139 and concomitant formation of the signal for the product ion at m / z 167 with the suggested mechanism in eq 1.7 The structure of the m / z 167 (O(&MnC2H6 ~t [(OC),Mn(H)(C2HS)- $ m / z 139 (OC)@n(H)2(C2H&] (O%Mn(C2H4)- + H2 (1) m / z 167 ion was characterized as the 16-electron q2-C2H4complex from its further ion-molecule reactions with D2 where up to four H/D exchanges were observed ( m l z 168-171) and with H2S and (CH3),SiH which yield the corresponding adducts of H-S6 and H-Si bond oxidative additi~n.~"Statistical correction of the rate
+
-
( 1 ) Crabtree, R. H. Chem. Reu. 1985, 85, 245-269. (2) Janowicz, A. H.; Bergman, R. G. J . Am. Chem. Soc. 1982,104,352354; 1983, 105, 3929-3939. (3) Hoyano, J. K.; Graham, W. A. G. J . Am. Chem. SOC.1982, 104, 3723-3725. (4) Janowicz, A. H.; Periana, R. A.; Buchanan, J. M.; Kovac, C. A.; Stryker, J. M.; Wax, M. J.; Bergman, R. G . Pure Appl. Chem. 1984, 56, 13-23. (5) (a) McDonald, R. N.; Chowdhury, A. K. J . Am. Chem. Soc. 1985,107, 4123-4128. (b) McDonald, R. N.; Chowdhury, A. K.; Setser, D. W. Ibid. 1980, 102, 64916498. (6) McDonald, R. N.; Chowdhury, A. K.; Jones, M. T. J. Am. Chem. Soc. 1986,108, 3105-3107. (7) For some general references for the steps in eq 1, see ref 1 and: Parshall, G. W. Homogeneous Catalysis; John Wiley: New York, 1980. (8) Generally, 15- and 16-electron metal complex negative ions oxidatively add HzS and (CH,),SiH forming termolecular adducts with apparent bimolecular rate constants of 1Wi0 to 1W" cm3molecule-' If the coordinatively unsaturated complex contains a hydride ligand, Hzis usually reductively eliminated in the bimolecular reaction. (9) The fast bimolecular reactions of the product ions of m / z 167, 207, 195, and 181 with SO2yield (OC)IMn(SOz)-withloss of C2H4,c-C5Hs,C4Hs, and C3H6.respectively.
+'.
0002-7863/86/1508-8097$01.50/0
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Table I. Kinetic Data for the Reactions of (OC)3Mn- with Alkanes in This Study statistically corrected k / C H bond,b cm3 molecule-I SKI
cm3 molecule-I s-l ktom,,"
alkane C2H6
c-CSHI~ (CH,)$H
(8.0 (9.5 (3.4
* 0.1) X ** 0.5) X lo-" 0.4) X IO-"
1.3 9.5 1.5 2.0
k,,l(CH)b
X (lo) X lo-'' (2') X 10-l' ( l o )
1 7
x 10-1' (30) 13 (CHJ2CH2 (2.2 f 0.2) X lo-" "The errors are the maximum deviations from the average rate constants determined in at least three kinetic runs for each alkane. bThe average ktOhlis used to calculate the (LICH bond) values (see text).
constant for reaction 1 yields (k/1° CH bond) (Table I). The reaction of (OC)3Mn- with cyclopentane also gave the product ion of dehydrogenation, m / z 207 (eq 2). However, the
-
(OC)3Mn- + c-CSHlo m / z 139
-H2
-
[(OC),M~(Q~-C-C,H,)-]
(oC)3Mn(H)(113-c-C,H7)- (2) m / z 207 absence of reaction of the m / z 207 ion with the above neutral^^^^ used with the m / z 167 ion suggests that the m / z 207 ion is an 18-electron complex negative ion formed by oxidative addition of an allylic C H bond to Mn in the intermediate olefin complex. The rate constant and ( k / 2 O C H bond) are give in Table I. The reaction of (OC)3Mn- with (CH,),CH similarly gave the m / z 195 product ion (eq 3). The product ion of m / z 195 was (OC),Mn-
+ (CH3),CH
-H2
[(OC)3Mn--(>=)]
-
(OC)3Mn(H)[Q3-(2-CH3)C3H41(3) m / z 195
also characterized as the 18-electron hydridc-r-allyl structure in eq 3 based on its lack of reaction with D2, H2S, and (CH,),SiH.8,9 (CH3)$H contains nine 1' CH bonds vs. one 3O CH bond for potential intermolecular oxidative addition to (OC)3Mn-. If we assume that (k/1° C H bond) obtained from the reaction of (OC)3Mn- with C2H6applies to the reaction with (CH3)$H and correct it for the 14% increase in the number of collisions between (OC),Mn- and (CH3)$H vs. C2H6 due to the larger polarizability and dipole moment of (CH3)$H, ( k / 1' CH bond) = 1.5 X cm3 molecule-' s-l in (CH3)3CH. Therefore, the kinetic contribution of reaction by the nine 1O CH bonds of (CH,),CH is 1.4 X lo-" cm3 molecule-' s-' which is 41% of ktotalfor this reaction (Table I). The remaining 59% of k,,', 2.0 X lo-" cm3 molecule-' s-I, is due to oxidative addition of the 3 O CH bond in (CH3)$H based on the above assumption. This analysis is qualitatively supported by the determination of a smaller kinetic deuterium isotope effect for the 1' CH bonds in (CH3),CH (k(CH3),CH/ ~(cD,),cH = 1.3) compared to C2H6 (kC2H6/kC2D6 = 2.2). Assuming that other factors are equal, this result shows a significantly lower contribution of oxidative addition of the 1O CH bonds to k,,,, for the reaction of (OC)3Mn- with (CH3),CH than with C2H6. Since these overall reactions of dehydrogenation of the alkane by (OC)3Mn- involve the two steps of initial intermolecular oxidative addition followed by intramolecular migration of a hydrogen from an alkyl @-carbonto Mn, it was essential to eliminate the contribution of the intramolecular second step to the observed ktotal'sfor these reactions. We believe that the results of the reactions of (OC)3Mn- with (CH3)2CH2and (CHJ2CD2 accomplish this end. The reaction of (OC)3Mn- with [CH,),CH2 yields the product ion of m / z 181 characterized as the 18-electron hydride-*-allyl complex in eq 4 by failure of the m / z 18 1 ion to react with H2S and (CH3)3SiH.8,9
-
(OC)3Mn- + (CH3)2CH2
(0C),Mn(H)(q3-C3H,)m / z 181
+ H2
(4) In the reaction of (OC)3Mn- with (CH&CD2, complex 1 will be produced as the intermediate irrespective of initial 1 ' CH or 0 1986 American Chemical Society
J . Am. Chem. SOC.1986, 108, 8098-8100
8098
2 O CD bond oxidative addition followed by @-Dor @-Hmigration, respectively. If the intramolecular @-migrationsand their microscopic reverse rearrangements are slow compared to the fast unimolecular fragmentation of 1, the sole product will be the m / z 182 ion formed by reductive elimination of H D from 1. The results of the reaction with (CH3)&D2 in eq 5 with formation of about
coupling constants
coupling c o n s t a n t s ( H i 1
(HI]
J15,16
=
3.5
J151,16 =
J16,17
=
9.3
di7,20
=
10.5
'16.17
J20,21
=
6.4
J20,22,
=
14.5
J20,22n
J20,22p =
4.0
J22n,22.
14.4
J22,.22i
~
9.3
J15,16
3.7
J15j,16 =
6'4
'20.21
=
3.8
J20,22F = 14'7
=
14.5
=
7.7
=
Figure 1. N M R data in CDCI, (360 MHz); chemical shifts in 6 (ppm).
equal amounts of the m / z 182 and 183 ions clearly show that H/D scrambling in 1 is extensive, but not statistical, during the brief lifetime of the excited ion. This result means that intramolecular rearrangements of H and D between Mn and the @-carbonsare fast and reversible and will not contribute significantly to the observed kinetics. These kinetic results establish the reactivity order for oxidative addition of aliphatic C H bonds to (OC)3Mn- as 1' < 2' < 3O, although the quantitative values given may be in error. The absence of observed oxidative addition of 3O C H bonds in the condensed phase4 is probably due to the steric bulk of the transition-metal complex used rather than a significant difference in the intrinsic reactivities of lo, 2O, and 3 O C H bonds in the two phases.
Acknowledgment. We thank the National Science Foundation for support of this research and Professors David Macomber and Eric Maatta for helpful discussions.
Chirality Transmission via a 6-Endo Free-Radical-MediatedCyclization Process. Regio- and Stereocontrolled Synthesis of the 22-Hydroxylated Steroid Side Chains Masato Koreeda* and Irene A. Georget Department of Chemistry, The University of Michigan Ann Arbor, Michigan 48109 Received August 28, 1986
Primarily through the extensive efforts of Stork,' Hart,2 and C ~ r r a nC-C , ~ bond formation via free-radical-mediated cyclization reactions now has a firmly established role in synthetic organic chemistry as a highly versatile and often indispensable method 'Interdepartmental Medicinal Chemistry Program Participant. (1) (a) Stork, G.; Baine, N. H. J . Am. Chem. SOC.1982, 104, 2321. (b) Stork, G.; Mook, R., Jr. Ibid. 1983,105, 3720. (c) Stork, G.; Mook, R., Jr.; Biller, S. A.; Rychnovsky, S. D. Ibid. 1983, 105, 3741. (d) Stork, G.; Sher, P. M. Ibid. 1983, 105, 6765. (e) Stork, G. In Selectivity-a Goal for Synthetic Efflciency; Bartman, W., Trost, B. M., Eds.; Verlag Chemie: Basel, 1984; pp 281-298. (f) Stork, G.; Kahn, M. J. Am. Chem. Soc. 1985, 107, 500. (g) Stork, G.; Baine, N. H. Tetrahedron Lett. 1985,26,5927. (h) Stork, G.; Sher, P. M. J. Am. Chem. Soc. 1986, 108, 303. (i) Stork, G.; Mook, R., Jr. Tetrahedron Lett. 1986, 27, 4529. (2) (a) Hart, D. J.; Tsai, Y.-M. J. Am. Chem. Soc. 1982, 104, 1430. (b) Choi, J.-K.; Hart, D. J.; Tsai, Y.-M. Tetrahedron Lett. 1982, 23, 4765. (c) Chuang, C.-P.; Hart, D. J. J . Org. Chem. 1983, 48, 1782. (d) Burnett, D. A.; Choi, J.-K.; Hart, D. J.; Tsai, Y.-M. J . Am. Chem. SOC.1984, 106, 8201. (e) Hart, D. J.; Tsai, Y.-M. Ibid. 1984, 106, 8209. (f) Hart, D. J.; Huang, H.-C. Tetrahedron Lett. 1985, 26, 3749. (9) Choi, J.-K.; Hart, D. J. Tetrahedron 1985, 41, 3959. (h) Chenera, B.; Chuang, C.-P.; Hart, D. J.; Hsu, L.-Y. J. Org. Chem. 1985, 50, 5409. (3) (a) Curran, D. P.; Rakiewicz, D. M. J. Am. Chem. SOC.1985, 107, 1448; (b) Tetrahedron 1985, 41, 3943. (c) Curran, D. P.; Chen, M.-H. Tetrahedron Lett. 1985, 26, 4991. (d) Curran, D. P.; Kuo, S.-C. J. Am. Chem. Sac. 1986, 108, 1106. (e) Curran, D. P.; Chen, M.-H.; Kim, D. Ibid. 1986, 108, 2489.
0002-7863/86/ 1508-8098$01.50/0
Scheme I
of skeleton con~truction.~ The large volume of data delineating radical reactivity compiled over the past several decades un(4) Reviews: (a) Hart, D. J. Science (Washington, D.C.) 1984, 223, 883. (b) Giese, B. Angew. Chem., f n t . Ed. Engl. 1985, 24, 553. For other recent leading references on intramolecular cyclizations of carbon-centered radicals, see: (c) Bakuzis, P.; Campos, 0.0.S.; Bakuzis, M. L. F. J. Org. Chem. 1976, 41, 3261. (d) Biichi, G.; Wiiest, H. Ibid. 1979, 44, 546. (e) Danishefsky, S.; Chackalamannil, S.; Uang, B.-J. Ibid. 1982, 47, 2231. (f) Burke, S. D.; Fobare, W. F.; Armistead, D. M. Ibid. 1982, 47, 3348. (g) Ueno, Y.; Chino, K.; Okawara, M. Tetrahedron Lett. 1982,23,2575. (h) Ueno, Y.; Chino, K.; Watanabe, M.; Moriya, 0.;Okawara, M. J. Am. Chem. Soc. 1982,104,5564. (i) Okabe, M.; Tada, M. J . Org. Chem. 1982, 47, 5382. G) Marinovic, N. N.; Ramanathan, H. Tetrahedron Lett. 1983, 2 4 , 1871. (k) Corey, E. J.; Pyne, S. G. Ibid. 1983,24, 2821. (1) Clive, D. L. J.; Beaulieu, P. L. J. Chem. SOC.,Chem. Commun. 1983, 307. (m) Beckwith, A. L. J.; O'Shea, D. M.; Roberts, D. H. Ibid. 1983, 1445. (n) Bachi, M. D.; Frolow, F.; Hoornaert, C. J . Org. Chem. 1983, 48, 1841. (0)Clive, D. L. J.; Beaulieu, P. L.; Set, L. Ibid. 1984, 49, 1313. (p) Nishiyama, H.; Kitajima, T.; Matsumoto, M.; Itoh, K. Ibid. 1984, 49, 2298. (9) Molander, G. A,; Etter, J. B. Tetrahedron Lett. 1984, 25, 3281. (r) Ladlow, M.; Pattenden, G. Ibid. 1984, 25, 4317. (s) Corey, E. J.; Kang, M.-C. J . Am. Chem. SOC.1984, 106, 5384. (t) Scheffold, R. Chimia 1985,39,203. (u) Wilcox, C. S.; Thomasco, L. M. J . Org. Chem. 1985,50,546. (v) Padwa, A.; Nimmesgern, H.; Wong, G. S. K. Tetrahedron Lett. 198526.957. (w) Keck, G. E.; Enholm, E. J. Tetrahedron Lett. 1985, 26, 3311. (x) Beckwith, A. L. J.; Roberts, D. H.; Schiesser, C. H.; Wallner, A. Ibid. 1985, 26, 3349. (y) Ernst, A. B.; Fristad, W. E. Ibid. 1985, 26, 3761. (z) Snider, B. B.; Mohan, R.; Kates, S. A. J. Org. Chem. 1985, 50, 3659. (aa) Padwa, A.; Nimmesgern, H.; Wong, G. S. K. Ibid. 1985, 50, 5620. (bb) Angoh, A. G.; Clive, D. L. J. J . Chem. SOC.,Chem. Commun. 1985,941,980. (cc)Shankaran, K.; Sloan, C. P.; Snieckus, V. Tetrahedron Lett. 1985, 26, 6001. (dd) Leonard, W. R.; Livinghouse, T. Ibid. 1985,26, 6431. (e) Nakai, E.; Kitahara, E.; Sayo, N.; Ueno, Y.; Nakai, T. Chem. Lett. 1985, 1725. (ff) Jones, K.; Thompson, M.; Wright, C. J . Chem. Soc., Chem. Commun. 1986, 115. (gg) Mohammed, A. Y.; Clive, D. L. J. Ibid..1986, 588. (hh) Winkler, J. D.; Sridar, V. J. Am. Chem. SOC.1986, 108, 1708. (ii) Tsang, R.; Fraser-Reid, B. Ibid. 1986, 108,2116. (jj)Porter, N. A.; Magnin, D. R.; Wright, B. T. Ibid. 1986, 108, 2787. (kk) Molander, G. A.; Etter, J. B. J. Org. Chem. 1986, 51, 1778. (11) Meijs, G. F.; Beckwith, A. L. J. J. Am. Chem. SOC.1986, 108, 5890. (mm) Beckwith, A. L. J.; Roberts, D. H. Ibid. 1986, 208, 5893. (nn) Beckwith, A. L. J.; OShea, D. M. Tetrahedron Lett. 1986,27,4525. For intermolecular versions, see ref 4b and: (00) Giese, B.; Heuck, K. Chem. Ber. 1979, 112, 3759. (pp) Giese, B.; Horler, H.; Zwick, W. Tetrahedron Lett. 1982, 23, 931. (qq) Kozikowski, A. P.; Nieduzak, T. R.; Scripko, J. Organometallics 1982, 1,675. (rr) Adlington, R. M.; Baldwin, J. E.; Basak, A,; Kozyrcd, R. P. J . Chem. SOC.,Chem. Commun. 1983,944. (ss) Baldwin, J. E.; Kelly, D. R.; Ziegler, C. B. Ibid. 1984, 133. (tt) Baldwin, J. E.; Adlington, R. M.; Basak, A. Ibid. 1984, 1284. (uu) Giese, B.; Gonzllez-GBmez, J. A,; Witzel, T. Angew. Chem., In!. Ed. Engl. 1984, 23, 69. (w) Keck, G. E.; Kachensky, D. F.; Enholm, E. J. J. Org. Chem. 1984,49, 1462. (ww) Giese, B.; Groninger, K. Tetrahedron Lett. 1984, 25, 2743. (xx) Kraus, G. A.; Landgrebe, K. Ibid. 1984, 25, 3939. (yy) Fristad, W. E.; Peterson, J. R. J . Org. Chem. 1985.50, 10. (zz) Keck, G. E.; Kachensky, D. F.; Enholm, E. J. Ibid. 1985,50,4317. (aaa) Keck, G. E.; Byers, J. H. Ibid. 1985, 50, 5442. (bbb) Keck, G. E.; Enholm, E. J.; Wiley, M. R. Tetrahedron 1985, 41,4079. (ccc) Giese, B.; Witzel, T. Angew. Chem., In?.Ed. Engl. 1986, 25, 450. (ddd) Baldwin, J. E.; Adlington, R. M.; Birch, D. J.; Crawford, J. A,; Sweeney, J. 8. J . Chem. SOC.,Chem. Commun. 1986, 1339. (eee) Gerth, D. B.; Giese, B. J . Org. Chem. 1986, 51, 3726.
0 1986 American Chemical Society
